write frames to png files and some clean up

datatypes.go

@@ -69,6 +69,10 @@ type ImageDescriptor struct {
 	Packed byte   // image and color table data information
 }
 
+/********************/
+/* EXTENSION BLOCKS */
+/********************/
+
 /*
 GraphicsControlPacked {
 	0:   TransparentColorFlag
@@ -78,10 +82,6 @@ GraphicsControlPacked {
 }
 */
 
-/********************/
-/* EXTENSION BLOCKS */
-/********************/
-
 // Only available on 89a and comes after the global color table and before the 1st image
 type GraphicsControlBlock struct {
 	Packed                byte  // method of graphics disposal to use